The Constitution is just a piece of paper. The forces which gave the ideas on that paper life, are not, as you claim, "endangered", they are extinct. The federal government was never and can never be held to it's Constitutional role simply by passing a law (the Constitution). The forces created by that document were not simply obeying orders, they were standing up for their own self interests, which were pitted against each other to make REAL balance, REAL checks on power.
Removing the representation of the states was the end of that. Nothing but fear of being caught was then in the way of inevitable federal growth.
If you want a Republic again, you have to put back the force that worked against runaway federal government. Repeal 17.